I have a little over 130 lbs that I want to lose, and you are an inspiration!

I started working out this week. We have a pretty nice gym at work, but I've only been doing 30 min when I go up there because I don't want to overdo it. I've found that the treadmill hurts my back, so I ditched that and have been doing the eliptical and stationary bike. I want to do strength training but would prefer to do that at home.